As an image forming apparatus of an electrophotographic type, a printer has been known which has a photosensitive drum, on which a toner image is carried, and a transfer roller facing the photosensitive drum. The printer brings a leading end of a sheet into contact with the photosensitive drum, introduces the same between the photosensitive drum and the transfer roller by rotation of the photosensitive drum and transfers a toner image onto the sheet.
Specifically, related-art discloses a process cartridge which has a film member for guiding a sheet upstream of a photosensitive drum in a rotating direction thereof.
Another related-art discloses a process cartridge which uses a bent film, which can guide a sheet and is formed to be bent towards a transfer position, upstream of a photosensitive drum in a rotating direction thereof.
In the process cartridge disclosed in related-art, a conveyance speed of the sheet is increased so as to make a printing speed faster and a transfer current is increased so as to securely transfer a toner image onto the sheet in a short time. In this case, a discharge trace (rear end disarray) is apt to form on the sheet when a rear end of the sheet falls off the film member, which is a problem.
Regarding this, when the bent film is used as disclosed in related-art, the sheet can be guided till just in front of the transfer position. Therefore, it becomes difficult for the rear end of the sheet to fall off the film, so that it is possible to suppress the discharge trace from being formed.
However, in the process cartridge using the bent film, since the film is bent, the sheet repeatedly rubs against the bent part. As a result, the bent part is worn, which is a problem.